[Easy Unlock] Port the BluetoothThrottler class to native code.

components/proximity_auth/bluetooth_throttler_impl.cc

+// Copyright 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "components/proximity_auth/bluetooth_throttler_impl.h"
+
+#include "base/time/tick_clock.h"
+
+namespace proximity_auth {
+namespace {
+
+// Time to wait after disconnect before reconnecting.
+const int kCooldownTimeSecs = 7;
+
+}  // namespace
+
+BluetoothThrottlerImpl::BluetoothThrottlerImpl(
+    scoped_ptr<base::TickClock> clock)
+    : clock_(clock.Pass()) {
+}
+
+BluetoothThrottlerImpl::~BluetoothThrottlerImpl() {
+}
+
+base::TimeDelta BluetoothThrottlerImpl::GetDelay() const {
+  if (last_disconnect_time_.is_null())
+    return base::TimeDelta();
+
+  base::TimeTicks now = clock_->NowTicks();
+  base::TimeTicks throttled_start_time =
+      last_disconnect_time_ + GetCooldownTimeDelta();
+  if (now >= throttled_start_time)
+    return base::TimeDelta();
+
+  return throttled_start_time - now;
+}
+
+void BluetoothThrottlerImpl::OnConnectionClosed() {
+  last_disconnect_time_ = clock_->NowTicks();
+}
+
+base::TimeDelta BluetoothThrottlerImpl::GetCooldownTimeDelta() const {
+  return base::TimeDelta::FromSeconds(kCooldownTimeSecs);
+}
+
+}  // namespace proximity_auth